Comparison of chorionic villus sampling and amniocentesis for fetal karyotyping at 10 - 13 weeks' gestation [published erratum appears in Lancet 1994; 17: 344 (8925): 830] [see comments]. - Nicolaides,K.; Brizot,Md.L.; Patel,F.; Snijders,R. (Lancet, 1994)